ichidan verb, intransitive verb
butt in; crash; come uninvited
Colloquial and slightly negative; implies pushing oneself into a situation or place where one is not wanted.
彼はいつも人の会話にしゃしゃり出てくる。
He always butts into other people's conversations.
あいつ、またパーティーにしゃしゃり出てきたよ。
That guy crashed the party again.